Experimental and optimization studies of ultrasonic-assisted friction stir weldments of AA2014-T651 using graph theory

The present study focuses on development of mechanical characteristics in ultrasonic vibration assisted friction stir welding (UAFSW) of AA 2014-T651 weldment using graph theory algorithm and utility concept. A set of UAFSW experiments were carried out using plain and taper threaded cylindrical tool pin profile on AA 2014-T651 weldments at different levels of tool rotation speed and traverse speed and experimental results for the tensile strength, yield strength, percentage of elongation, impact strength, and micro hardness were collected. Microstructural studies were also made and correlated with the mechanical characteristics and found that the mechanical characteristics were increased. The process parameters were optimized by the proposed methodology as 1100 rpm of tool rotational speed and 40 mm/min of traverse speed. The tensile strength, yield strength, percentage of elongation, impact strength, and micro hardness were found to be 431.69 MPa, 307.47 MPa, 11.66%, 8.32 J, and 139 HV respectively at optimum working condition. The weld joint obtained using a taper threaded tool pin profiled tool with ultrasonic vibration possesses 90% of joint efficiency.